Cotton is a natural fiber grown on a cotton plant. The fibers (commonly referred to in the art as lint) grow in a boll on a stem of the cotton plant. Seeds are interspersed with the fiber in the boll. The lower part of the boll includes a dried portion of the envelope that contained the cotton bloom as it developed into the boll and is referred to in the art as a "burr." Most cotton in the United States is harvested ("stripped") by machines referred to in the art as "strippers." When the cotton boll is stripped from the plant by the stripper, the seeds are interspersed with the fiber and tightly bound to the hull of the seed. Mechanical strippers, while very efficient in harvesting the cotton, tend to collect burrs, leaves, stalks and other trash with the cotton bolls. Gins as well-known in the art for over 150 years have been used to mechanically separate cotton seeds from the lint. In conventional prior art gins, stationary ribs are alternately interspersed between gin saws to separate the seed from the lint and direct the seeds downward and away from the ginning point. One example of a gin with stationary ribs is illustrated in U.S. Pat. No. 4,433,454 issued to Salmon.
U.S. Pat. No. 3,315,021 issued to Jennings discloses a rotary rib gin which does not contain any stationary ribs. In the Jennings gin, the rotary ribs are disposed downwardly in relation to the seed cotton roll, which accumulates during the ginning process. The rotary ribs of the Jennings gin direct the trash (including seed, stems and burrs) upward toward the center of an accumulated seed cotton roll where the seeds and trash fall through a longitudinal slit in a seed conveyor cover and are removed by a spiral seed conveyor. In the Jennings gin, the seed, stems and burrs will tend to fall downwardly due to gravity and may repeatedly contact the rotary ribs and gin saws before entering the slit in the conveyor cover whereby they are removed from the gin. In addition to being inefficient, such repeated contact may contribute to trash lodging between the gin saw blades and the rotary ribs which may result in a gin fire.
One of the most serious problems in prior art gins are rib fires. Rib fires are caused when trash such as cotton hulls, burrs, stems, and/or green or wet cotton seed lodge in between a gin saw blade and the ribs disposed on each side of the gin saw blade. The gin saw blade may rotate at speeds of approximately 700 RPM. Friction between the gin saw blade and the trash will cause a build up of heat. The cotton lint is very flammable. A rib fire occurs when the heat builds to the point of spontaneous combustion.
Rib fires are very dangerous and destructive. A need exists in the ginning industry for a gin design that efficiently prevents trash from lodging between the ribs and the gin saw blades. The rotary rib of the present invention effectively prevents trash and cotton seeds from lodging between the gin saw blades and the ribs.